lift bridge

Pont Jacques-Chaban-Delmas

Vertical-lift bridge – a type of movable bridge in which a span rises vertically while remaining parallel with the deck. The counterweights in a vertical lift are only required to be equal to the weight of the deck. As a result, heavier materials can be used in the deck, and so this type of bridge is especially suited for heavy railroad use.

Some examples

  • Slauerhoffbrug Flying Drawbridge – a fully automatic bascule bridge (aka tail bridge) lifts a section of the road into the air to make room for passing water traffic. By doing away with the hinged mechanism of typical two-part raising tail bridges, this impressive piece of engineering can raise and lower much quicker than its traditional counterparts, allowing for minimum disruption to traffic on river or road.
  • Pont Gustave-Flaubert – crossing the Seine at Rouen, this lift bridge is the highest vertical-lift bridge in Europe, allowing ships up to 55 m tall to pass under it. It is 670 m long, with a span of 116 metres. A striking design feature, the two road sections are mounted outside the central towers.

What’s the problem?
Vertical-lift bridge -The biggest disadvantage to the vertical-lift bridge (in comparison with many other designs) is the height restriction for vessels passing under it. This is a result of the deck remaining suspended above the passageway.

  • Ask – What are the limitations of the lift bridge design? What are the advantages? What would it cost when compared to other types of bridge construction? When is a lift bridge likely to be the best choice?
  • Imagine – Most vertical-lift bridges use towers, each equipped with counterweights. Some use hydraulic jacks located below the deck.
  • Design, Build – The counterweights in a vertical lift are only required to be equal to the weight of the deck,
  • Improve – With modern materials, the towers can be taller than in the past. By combining bridge designs, the new design uses balance beams to lift the deck, with pivoting bascules located on the top of the lift towers.

That’s engineering

Engineering ideas

  • moveable, vertical, suspend, hydraulic, hinge, pivot

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